Trevor Beck, of Oturahua, asks :-

What is the cause of the misshapen carrot, the only one in a row I planted.

Bob Fullerton, a plant pathologist with Plant and Food Research, responded.

I would say that the taproot has been damaged in some way, for example by being nipped off by an insect at an early stage of growth (where the point of branching now is) and the root has simply formed a series of branches each of which has developed as a ‘carrot’. A carrot is simply as taproot modified as a storage organ which supports the flowering growth in the second year – they are typically biennials. In this case instead of a single storage root it is a series of branched storage roots.